PHP Warning - Only variables should be passed by reference

Hi,

Still going through checking on all plugin warnings and errors. I've traced one back to your Domain Mapping plugin, originating from classes/class.domainmap.php on lines 603/606/609, where it sets the cookie on login for mapped domains. I'm receiving the notice/warning "Only variables should be passed by reference" about ten to fifteen thousand times a day.

Cheers,

Ed